The traditional foreign exchange market moves $6.6 trillion every single day. It also settles most of those trades on a T+1 or T+2 basis, meaning your money sits in limbo for a day or two while intermediaries do their thing.
Circle StableFX is a new institutional-grade FX engine designed to settle stablecoin currency pairs instantly, around the clock, using smart contracts on the Arc blockchain. The platform went live on a public testnet on November 13, 2025, following Arc’s own testnet launch on October 28.
How StableFX actually works
StableFX uses a Request-for-Quote (RFQ) execution model that aggregates pricing from multiple liquidity providers. Instead of negotiating with one bank, institutional traders get competitive quotes pulled from several sources, which means tighter spreads and lower slippage.
The settlement itself happens through automated payment-versus-payment (PvP) smart contracts. Both sides of a trade settle simultaneously onchain, which effectively eliminates the counterparty risk that keeps traditional FX treasurers up at night.
